Grain‐Boundary‐Rich Artificial SEI Layer for High‐Rate Lithium Metal Anodes

Abstract The sluggish lithium diffusion at the electrode/electrolyte interface is one of the main obstacles to achieve superior rate capability of Li metal anodes for rechargeable batteries. Herein, a dense and uniform inorganic solid electrolyte interface (SEI) layer composed of ZrO 2 , Li 2 O, Li 3 N, and LiN x O y is constructed on the surface of Li metal via the spontaneous reaction between Li metal and zirconyl nitrate (ZrO(NO 3 ) 2 ) solution in dimethyl sulfoxide. The abundant grain boundaries in the artificial SEI created by the multicomponent enable the rapid diffusion of Li ions at the interface. As a result, the Li metal anode treated with zirconyl nitrate (LiZrO(NO 3 ) 2 @Li) delivers a stable cycle performance of over 550 h at a high current density of 10 mA cm −2 and a high areal capacity of 10 mAh cm −2 . When paired with a high‐loading LiCoO 2 cathode (19 mg cm −2 ), the LiZrO(NO 3 ) 2 @Li anode shows much enhanced rate performance and long‐term cycle stability without Li dendrite formation. The construction of an inorganic SEI layer with a high density of grain boundary provides new insights for the design of high‐rate and dendrite‐free Li metal anodes for high‐energy‐density batteries.